A wide variety of types of structures for disposable absorbent articles used to collect body fluids are known in the art. Commercial absorbent articles include diapers, adult incontinence products, catamenials and bandages. Disposable products of this type comprise components for receiving, absorbing and retaining fluids. Typically, such articles include a liquid permeable topsheet, an absorbent core and a liquid impermeable backsheet.
One of the main objectives in developing absorbent articles is to utilize the entire capacity of the absorbent article. In general, products of the type described above typically distribute liquids deposited on the topsheet in a circular pattern. Since such structures generally have a length that exceeds their width, this results in liquids reaching the longitudinal side edges of the absorbent article before the end regions of the absorbent article are fully utilized. When liquids reach the longitudinal side edges of the absorbent article, this increases the chance for leakage from the sides of the product, despite available absorbent capacity in the end regions of the absorbent article.
In the past, a number of efforts have been made to direct the flow of exudates in an attempt to utilize more of the absorbent capacity of an absorbent article. A number of these efforts have used absorbent means or densification of absorbent means. Some of such efforts are described in U.S. Pat. No. 4,678,453 issued Jul. 7, 1987 to Holtman and U.S. Pat. No. 4,624,666 issued Nov. 25, 1986 to DeRossett, et al. Absorbent articles which use absorbent means to direct exudate flow, however, are typically subject to the disadvantage that the absorbent means will tend to become saturated which interferes with its liquid directing capabilities.
The better distribution and utilization of the capacity for absorption of menses and other bodily exudates in thin sanitary napkins having capacities great enough to handle medium to high menstrual flows is disclosed in U.S. Pat. Nos. 4,950,264 and 5,009,653, issued to Osborn, on Aug. 21, 1990 and Apr. 23, 1991, respectively. The distribution of exudates in the sanitary napkins described in these references is achieved at least in part by using a "wipe acquisition sheet" that distributes the exudates more evenly over an underlying absorbent core.
Still other sanitary napkins have been developed which use fibers having intra-fiber capillary channels, particularly on their exterior surfaces for transporting liquids. Examples of such sanitary napkins are disclosed in PCT International Publication Nos. WO 93/01779 to WO 93/01783 and WO 93/02251, all of which publications are incorporated by reference herein. Several of these publications disclose sanitary napkins that use capillary channel fibers that may be arranged in the form of a tufted bundle (or "bun"). The sanitary napkins described in these international patent publications work quite well. However, capillary channel fibers can be quite expensive for use in disposable absorbent articles. Therefore, the search for alternative sanitary napkins has continued.
Still other types of absorbent structures are known in the art. For example, U.S. Pat. No. 4,361,151 issued to Fitzgerald discloses a tampon formed from braided slivers of absorbent material. The braided structure in the Fitzgerald tampon is hydrophilic and serves as the primary absorbent component of the tampon. The Fitzgerald patent, however, does not disclose a sanitary napkin or a structure for improving the utilization of the entire capacity of a sanitary napkin.
Thus, a need exists for a sanitary napkin having an alternative type of liquid distribution mechanism for directing liquids to better utilize the entire capacity of the sanitary napkin, and particularly to one that does not use an absorbent mechanism for liquid distribution.
It is, therefore, an object of the present invention to provide disposable absorbent articles that have an improved mechanism for distributing the exudates throughout the absorbent core of the article.
It is another object of the present invention to provide absorbent articles that have a mechanism for distributing body exudates that will not become saturated and interfere with its liquid distribution capability.
It is another object of the present invention to provide absorbent articles having the above characteristics which are easily and inexpensively manufactured.
These and other objects of the present invention will be more readily apparent when considered in reference to the following description and when taken in conjunction with the accompanying drawings.